Method of making faced building blocks and the like



June 24, 1952 J. A. KNIGHTON METHOD OF MAKING FACED BUILDING BLOCKS AND THE LIKE 3 Sheets-Sheet 1 Filed Aug. 19, 1949 w a k n W m .4

0 r TORNEYs June 24, 1952 J. A. KNIGHTON 2,601,532

METHOD OF MAKING FACEZD BUILDING BLOCKS AND THE LIKE Filed Aug. 19, 1949 3 Sheets-Sheet 3 INVENTOR. c/RMLKS ,9. XIV/611701! Patented June 24, 1952 UNITED STATES PATENT OFFICE METHOD OF MAKING FACED BUILDIN BLOCKS AND THE LIKE The present application is a continuation-inpart of my co-pending application Serial No. 661,700, filed April 12, 1946, subject, Method of Making Concrete Building Blocks, which application is now abandoned.

My present invention relates to a method for making faced building blocks and the like, and while not limited thereto contemplates the provision of a method of the character designated by means 'of which blocks formed principally of ordinary concrete material shall have securely bonded to one or more faces a relatively thin layer of material such for instance as a cementmarble aggregate mixture, thus providing a block having one or more water-proof surfaces which are'smo'oth and attractive in appearance, and a block which lends itself to economical, mass production.

"It isthe prime object of my invention therefore to overcome the above difiiculties and to provide a method for'makin'g faced concrete building blocks and the like in which facing material in plastic condition is first placed in a shallow pan formed of material having the strength, anti-corrosion properties and smoothness of Stainless steel, the pan and its contents being vibrated at a given frequency and amplitude for a given period of time, being permitted to setfor' 'a given time, and then being placed in the mold box of a concrete block machine where the common cement-aggregate mixture for the body of the block is packed onto the facing material and bonded intimately therewith.

Another object is to provide a method of making such blocks in which a definite proportion of cement, aggregate and water forming the facing material is perfectly bonded to the block body material by feedin a, portion of the body material into the mold box in contact with the facing material, the pan preferably being placed on edge in the mold box, tamping this portion of the'body material and then feeding and tamping the remainder of the body material to complete the block.

"A suitable form of apparatus for carrying out my improved method is shown in the accompanying' drawings forming a part of this application'in which:

i 1 is a diagrammatic side elevational view of the apparatus for "fillinggvibrating and conveying the pans filled with facing material and the block making machine and kiln;

Fig. 2' is a flow sheet illustrating the steps in the process;

Fig. 3 .is an isometric view of the improved 5 Claims. (01. 18-60) 2 form of shallow pan for the plastic facing material; I

Fig; 4 is an isometric view of a block made in accordance with my improved method and with my improved apparatus;

Fig. 5 is an enlarged detail sectional view taken along line VV of Fig. 4;

Fig. 6 is an isometric view of an L-shaped pan especially adapted to form a block faced on one side and one end;

Fig. 7 is a View of the mold box of the block machine with a pair of pans in place therein and filled with common cement-aggregate mix for forming the body of the block; and;

Fig. 8 is a plan view of the mold box taken generally along line VIII-VIII of Fig. 7'.

Referring now more. particularly to Figs. 1 and 2 of the drawing, I show diagrammatically the method, materials'and apparatus used in making my improved block, the block itselfbeing indicated at A, Fig. 4. The body of the block comprises common cement-aggregate mix of the ordinary kind used for making concrete blocks, and bonded to one or more faces thereof as will be explained is a relatively thin layer of facing material F. As is understood some of the aggregate in the body material may be larger than the largest aggregate in the facing material. While the facing material may comprise other components, I prefer to make the same of a water-white portland cement mixture with some form-of natural stone, for instance marble particles, as the aggregate. More specifically, I have discovered that the desirable qualities of water proofness, density, and smoothness "may be obtained through the use of the following mixture for the facing material'in' the proportions set out? pounds of A inch size marble aggregate 100 pounds of /8 inch size marble aggregate 100 pounds of inch to dust size marble aggregate 94 pounds of white portland cement 36 pounds of water The materials just mentioned are placed in a rotary mixer II) where they are intimately mixed together in the manner well understood."

In order to provide the thin slab or layer of the facing material which may be handled while sufliciently plastic to adhere to the COmmOn cement material of the block body, Iemploy a metal pan or pallet indicated generally by the numeral I I, Fig. 3. As shown, the pan is of a shape in plan to conform to the shape of the surface of the block to be faced. Thus, in making the standard 8 x8 x 16 inch block the pan would be 8 inches wide and 1-6 inches long. In practice I have discoveredthat stainless steel is an admirably suitable material for such pan. In making the 8 x 8 x 16 blocks I have found that stainless steel of 20 gauge is sufliciently rigid and entirely practical.

The pan may be formed of a sheet of stainless steel with integrally formed, upstanding side and end walls I2 and I3. For the usual block forming operation the walls should be approximately of an inch high. The corners of the walls are left unjoined as indicated at II, and the walls preferably are disposed at an obtuse angle to the bottom, preferably including with the bottom an angle of approximately 95, thus providing a slight amount of draft for a purpose later to appear.

In commencing the process, the bottom and inner surfaces of the walls of the pan first are preferably given a thin coat of fast drying paste wax of the ordinary household type. After this wax is dry, a sufficient quantity of the plastic material from the mixer III to substantially fill the pan is placed therein. In actual practice I fill the pan to within approximately 5 inch of the top.

At I6 I indicate diagrammatically a vibrating table. This table comprises a level bed I! which may be a sheet of steel, and is vibrated by means of a weight 18 eccentrically mounted on a shaft IS.. The shaft is driven by means of a motor 2| through the medium of a belt 22, and the direction of the vibration comprises essentially vertical components. I have discovered that both the frequency and amplitude of the vibration are important factors in providing a thin, dense, smooth outer surface on the layer of facing material. When using the specific mix for .the facing material above given I have found that the shaft 19 should be rotated approximately 4,000 revolutions per minute, thus making the frequency of vibration approximately 8,000- ,cycles per minute.

The table should be so set that the amplitude of this vibration is on the order of of an inch.

After the pan is filled with plastic material I place the same on the table and the vibrator is operated at the above frequency and amplitude for approximately 20 seconds. I have further found that this time element is important in producing the desired density and smoothness of the facing material. This has the effect of causing the marble particles to stratify or at least for the same tomove upwardly in the pan.

As shown more particularly in Fig. 5 of the drawing the larger particles in the plastic facing material F move upwardly in the pan while it is being vibrated whereas the smaller particles and a large part of the cement remain in the bottom of the pan, which as will later appear becomes the outer face 23 of the block. I have discovered that vibration at the above frequency and amplitudefor the length of time given produces an' extremely dense, smooth outer surface 23. Further, by causing the smaller particles to move toward the bottom of the pan, the whole mass adheres more strongly to the bottom and sides than would be the case if the larger particles were distributed uniformly throughout the material. This is of particular advantage in that a pan filled and vibrated as above given may be quite readily inverted or placed on edge without the material After vibrating the pan and its contents I let the same stand for a period of from 6 to 18 minutes. To obtain this setting time in continuous production I may provide an inclined slide 24 having its highest end adjacent the vibrator l5 and its lower end adjacent a block machine indicated generally by the numeral 26 in which the composite block is to be formed. The slide is of a length to permit the pans to set for the desired time before the first one placed thereon is removed and placed in the block machine.

I have discovered that the time of setting should be controlled at least within 1 to 3 minutes in order to produce the best results. If the plastic facing material 23 while in the pan sets too long, upon forming the block as will be described a poor bond will be obtained. If it does not set long enough it will be found that the common cement ing the tamping while in the mold box, flow through the layer of material F, thus spoiling the outer surface 23. This setting time is important in causing the material to stay in place in the pan. The precise time of setting varies somewhat in accordance with the temperature and humidity of the surrounding atmosphere. I have found that under average humidity conditions if the temperature of the surrounding atmosphere is in the neighborhood of '75 to F., the optimum setting period is approximately 6 minutes; if 60 to 75 F. the optimum setting period is approximately 12 minutes; if 40 to 60 F. the optimum setting period is approximately 18 minutes. By observing these setting times as a step in the process being disclosed I have found that the common cement material for the body of the block intimately bonds with the facing material without the liability of its forcing its way to the bottom of the pan II. I thus eliminate the majority of culls due to faulty bonding along the line of juncture between the body of the block and the facing material and culls resulting from damage to the surface 23 of the facing material F.

After the material in the pan has set for the time indicated I place the same in the mold box 21 of a concrete block machine. As shown more clearly in Figs. '7 and 8, such a mold box comprises generally a bottom 28 having openings 23 therein through which slidably pass the usual cores 3i. In the form of machine which I preferably use, the rear wall 32 of the mold box proper is stationary and is'provided with a front 33 and end walls 34. The end walls 34 preferably are hinged as indicated at 36 to the bottom 28 whereby they may swing outwardly thus to strip the block from the box. A form of machine which is entirely suitable for carrying out my process is that manufactured by the Miles Manufacturing Company of Jackson, Michigan. In this particular machine, the entire mold box embodying the bottom 28, the front wall 33 and the end walls 34 is pivoted as at 31. The entire mold box may thus be moved from the dotted line position indicated in Fig. '7 to the full line position.

With the mold box as indicated revolved counterclockwise 90 about the point 31 as shown in dotted lines, Fig. 7, I first place on the front wall 33 a wooden pallet 38. On top of this wooden pallet, inupright position, I place a pan ll filled with the plastic facing material which has been vibrated and set as indicated. The end walls of the mold box are provided with two sets of clip members 39 into which the ends of the pan ll fit. When making double faced blocks, a second pan H is inverted and placed with its end overlying. the other set of clips- 39 ontheend walls '34. The entire mold box is now rotated clockwise 90: to the full line position shown in Fig.

the mold box is in the full line position of Fig. 'I.

The common concrete material for forming the body of the block is now fed from a suitable supply hopper 4l' undercontr-ol of a manually operable valve 42. Initially, only a small quantity of the material from the hopper 4| is placed in the mold box, say forinstance up to the dot dash line 43 With this quantity of concrete in the mold box the tampers 44 are lowered and this quantity of the material is packed in place. Next, and while the tampers still are operating 1 fill the remainderof the mold box between the surfaces of the facing material in the pans I I with sufficient common concrete material to completely form the block body. After tam-ping for a length of time sufficient to further pack and settle the common material, the shuttle hopper 46 is moved to the dotted line position indicated bringing into position on top of the mold box a strike-off plate, not shown. The tamping is continued to completely pack the block and the mold box is again revolved 90 counterclockwise about its pivot point 31'. The mold box is now opened up by swinging the end walls 34 outwardly. The block is now lifted from the mold box, the wooden pallet 38 serving as its support and is placed on a racked kiln car indicated generally at 41, Fig. l. The blocks now gointo a kiln indicated at 48 which is provided with means for supplying live steam through suitable pipes 49, and also is provided with coils for dry heating indicated at 5|. The blocks remain in the kiln approximately 6 hours under the two kinds of heat, that is 6 hours under wet heat and 6 hours under dry heat at a temperature of about 200 F. 7

Referring particularly to Fig. 6 of the drawing I show an L-shaped pan Ha, having one section longer than the other which may be used for facing blocks on one end and one side. pan is constructed of a sheet of stainless steel similarly to pan l l the walls are flared outwardly of the bottom and the corners are left unconnected as already explained. v

In using the pan I Is, I first fill the longer section with plastic facing material from mixer I0. I then vibrate the pan with the longer side flat on the table. I! of the vibrator IE. I next allow this vibrated material to stand for a length of time suificient for the same to harden slightly, usually from approximately one third the length of time given above for the setting of the fiat pans at the temperature set. forth. The shorter side is now filed with pastic facing material and holding the pan carefully with the short side flat on the table I7 and with a slightly reduced amplitude of vibration. I vibrate. this section of the pan. While offhand it would appear that this later vibration would dislodget-he material in the then vertically disposed section of the pan, I have found in practice that this is not the case, and the material in both sections of the pan may thus be vibrated sufficiently for the purposes indicated. The pan is now permitted to stand for a short time and may then be placed on edge in the mold box and the block formed in the manner explained.

After the blocks are dried and cured it will be found that the walls l2 and i3 of the pans H and I la may be disengaged quite easily from the sur- This 6 faces. by means ofa suitable tool such as a screw driver, the sides being sprung slightly to release the pans. The slight amount of draft due tothe angularity of the sides with respect to the bottom aids in this removal operation.

From the foregoing it. will. be apparent that I have devised an improved method for making faced concrete blocks and the like. In. actual operation I have found that my improved-process is effective in'ever-y. Way. Further, bythe use of the L-shaped pan Ila shown in Fig. 6 I am enabled to make concrete blocks or the like which are faced on one side and one. end. Also, it. will be apparent that I may, througli'suitable modifications. of the mold box arrangement, face the block either on one end or one side. I- have found that the stainless steel pan is ideal for the purpose intended since this material resists corrosion, does not permit. air to enter between the wet facing material and bottom, is rigid, and is capable of being formed to the shape desired. My improved blocks are. entirely waterproof and when erected with a. waterproof cement between the joints thereof provide a building which is L extremely durable and which needs no further waterproofing. In my experience with blocks made in accordance with my process I have had practically no difiiculty with separation at the interface between the common and facing materials. I attributethis intimate bonding of these materials to close adherence to the several steps in the process as herein set forth, and toa somewhat lesser extent, the specific compositionof the facing material, together with the use of the stainless steel pan. or pallet ll or Ila. I thus am enabled to provide in mass production concrete blocks in which the face is "of material of one type and the body of the block of material of another. type. For the common cement-aggregate mixture for the block body I prefer to use a mixture in which at least some of the aggregate is larger than the largest aggregate in the facing material. Sufficient water is used in the body material to make a mix having approximately the plasticity of the same when making ordinary cement blocks; That is; the bodymaterial is sufficiently dry that the. block is selfsustaining immediately after it is formedas i1: lustrated in Fig. l.

While I have shownmy invention in but two forms, it. will be obvious to those skilled in" the art. that it is not. so limited, but is susceptible of various other changes and modifications, without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are specifically set forth in the appended claims.

What I claim is:

1. Inthe manufacture of faced concrete building blocks wherein the facing material comprises one type of plastic cement-aggregate mi ture in which the aggregate is of different Sizes and the block body material comprises a plastic cementaggregate mixture of different type dry enough to be self sustaining immediately after the block is formed, the method comprising the steps of placing a quantity of said facing material in plastic condition in a shallow metallic pan, vibrating the pan and contents for a length of time to cause the larger sizes of the aggregate thereof to move out of contact with the bottom of the pan, permitting the vibrated contents to stand in the pan for a period of time suflicient only for the same to partially set to the extent that the contents of the pan will remain in the pan without substantial flow when it is held substantially vertically on edge, standing the pan on edge with the bottom thereof substantially vertical, bringing the block body material in plastic condition into direct contact with the surface of the facing material in the pan, and tamping the plastic body material to cause intimate bonding of the same with the facing material.

2. In the manufacture of faced concret blocks wherein the facing material comprises one type of plastic cement-aggregate mixture and the block body material comprises a plastic cement- .aggregate mixture of different type dry enough to be self -sustaining immediately after the block is formed, the method comprising the steps of substantially filling a shallow metallic pan with said facing material in plastic condition, subjecting the pan and its contents to vibration composed of motion which embodies essentially vertical components and for a length of time for the principal part of the aggregate in said facing material carried in the pan to move out of contact with the bottom of the pan, permitting the facing material in the pan to stand until partially set only to the extent that the material remains in the pan without substantial flow when the pan is placed vertically on edge, bringing the body block-material while in plastic condition into direct contact with the surface of the material in the pan, tamping said plastic body material in a direction substantially parallel with the surface of the facing material in the pan, permitting the faced block thus formed to set with the pan in place, and in then removing said pan.

3. In the manufacture of faced concrete building blocks and the like in which the facing material comprises a mixture of natural stone particles some of which are of different size from the others and all of which are of fractional inch size mixed with cement and water and in which the material for forming the body of the block comprises a common cement-aggregate-water mixture dry enough to be self' sustaining immediately after the block is formed, the method which comprises substantially filling a shallow metallic pan with a facing material in plastic condition, vibrating the filled pan for a period of time sufiicient to cause the majority of the stone particles of larger size to move out of contact with the bottom of the pan, allowing the facing material to stand in the pan for a period of time suflicient only for the mixture therein to partially set to the extent that the material in the pan remains therein without substantial flow when the pan is held vertical, placing the pan on edge in the mold box of a concrete block machine with the surface of the facing material therein facing inwardly of the mold box, placing a portion of the total amount of the plastic material required for the block body in the mold box in direct contact with the lower portion of the surface of the facing material, tamping the said portion of the plastic material, supplying the mold box with the remainder of the plastic body material and tamp- 8 ing the vsame, removing the composite block so formed with the pan in place thereon, permitting the block to fully set with the pan in place, and in then removing the pan from the said block.

4. .The method as set forth in claim 3 in which the said remainder of the plastic body material is supplied to the mold box concomitantly with the tamping operation.

5. In the art of making faced building blocks in which the facing material comprises a cementwater mixture containing natural stone particles from approximately A, inch size to dust size and the body of the block comprises a cement-wateraggregate mixture in which the aggregate comprises solids at least some of which are larger than A, inch in size and which is dry enough to be self sustaining after the block is formed, the method of intimately bonding a layer of said facing material of approximately inch thickmass to a surface of said block during the manufacture thereof which comprises placing a layer gof said facing material in plastic condition in a metallic pan having side and end walls approximately inch high, vibrating the pan and its contents for a length of time sufficient to cause the majority of the larger sizes of aggregate in the facing material to move out of contact with the bottom of the pan, allowing the facing material to stand at rest in the pan until the same partially sets only to the extent that the contents remain in the pan when the same is held substantially vertically on edge, placing the pan and its contents on edge in the mold box of a concrete block forming apparatus, partially filling the mold box with the material for forming the body of the block while in plastic condition, tamping the body material in the partially filled mold box, subsequently completing the filling of the mold box with plastic body material, continuing the tamping operation until the body and facing material bond directly together along the meeting surfaces thereof, removing the block thus formed from the mold box with the pan in place, and removing the pan after the block has set.

JAMES A. KNIGHTON.

REFERENCES CITED 1 The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 60,310 Wiggin Dec. 4, 1866 719,244 Mooney Jan. 27, 1903 862,367 Zagelmeyer (III) Aug. 6, 1907 1,086,116 Zagelmeyer (H) Feb. 3, 1914 1,164,099 Kline Dec. 14, 1915 1,170,791 Zagelmeyer (I) Feb. 8, 1916 1,486,056 Straub Mar. 4, 1924 1,550,950 Cowell Aug. 25, 1925 1,676,153 Palmer July 3, 1928 1,701,619 Kendall Feb. 12, 1929 2,018,192 Sexton Oct. 22, 1935 2,034,164 Van Kamerik Mar. 17, 1936' 2,189,872 Ulrich Feb. 13, 1940 

